Crystallization Kinetics of 50% W Particles/Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 Metallic Glass Matrix Composite

Abstract

The crystallization kinetics of the 50% W particles/Zr41.2Ti13.8Cu12.5Ni10Be22.5 metallic glass matrix composite were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The results showed that the crystallization and the glass transition of the composite both have a kinetic effect. The characteristic temperatures Tg and Tx of the composite are linearly related to the natural logarithm of the heating rate (lnφ), and the presence of W particles increases the dependence of the glass transition on the heating rate. With the addition of W particles, the viscosity of the amorphous matrix in the supercooled liquid region increases, which hinders the spread and migration of the alloy elements and causes the thermal stability of the supercooled liquid to improve. In the isothermal crystallization, the mode of nucleation and the growth process of the crystal changes with the annealing temperature. The Avrami exponent with the crystallized fraction at 698 K was about 2.5 in the middle stage of the crystallization, implying three-dimensional growth with a constant nucleation rate.

Keywords

• crystallization kinetics
• W particles
• metallic glass matrix composite
• thermal stability